The present disclosure relates to composite filaments, particularly, filaments of polymer coated composite comprising metal nanoparticles dispersed throughout the composite matrix, for use in Fused Deposition Modelling (FDM).
The medical community's reliance on three dimensional 3D printing for various applications is rapidly increasing and covers areas such as tissue and organ fabrication, customizable devices such as prosthetics, mouth guards, orthotics, hearing aids and implants, and pharmaceutical exploration related to controlled drug delivery and personalized drug production. Many of these medical applications require composite material that can inhibit bacterial, microbial, viral or fungal growth. Other products for 3D printing such as kitchen tools, toys, education materials and countless household items also provide a favorable environment for bacteria growth, and therefore antibacterial composite materials are also desirable for use in connection with these products. Due to the layered construction of 3D printed material, the potential for bacterial growth can be very significant, especially since certain bacterial strains can actually thrive within the detailed structural make-up of these materials. Washing alone does not completely sterilize the surfaces and crevasses of these products.
Therefore, there exists a need for new materials with antibacterial properties for 3D printing. One of the 3D printing methods is FDM, which is a common additive manufacturing (3D printing) technique. FDM is an additive layer manufacture technology for fabricating physical, 3D objects from computer-aided-design (CAD) models. FDM technology can process common 3D printing materials, such as, polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and high-density polyethylene (HDPE). FDM operates on the principle of heating and then extruding a feedstock material, typically as a series of stacked, patterned layers, thereby to form a build. FDM process employs molten thermoplastic/polymers as build materials for making 3D articles via the extrusion of the molten plastics. This modelling process is a multi-step approach where a computer-aided design is rendered, in the case of medical applications this model would come from an ultrasound, computed tomography scan or magnetic resonance image. This design is then processed by software which sets the desired build parameters. The file data is used by the FDM apparatus to build the article. The spool of filament material is fed into a headed extrusion head which delivers the semi-liquid material onto the build platform in a layer-by-layer fashion. As the model is built, the layers solidify upon deposition due to the temperature differential of the build chamber. In some cases the head can also extrude a removable support material which acts as a scaffold to hold the article layers in place as it cools. This support material can later be removed via heating, breaking off or washing (in ultrasonic vibration tank). A layer by layer method of depositing materials for building a model is described in U.S. Pat. No. 5,121,329 which is incorporated herein by reference. Examples of apparatus and methods for making three-dimensional models by depositing layers of flowable modeling material are described in U.S. Pat. No. 4,749,347, U.S. Pat. No. 5,121,329, U.S. Pat. No. 5,303,141, U.S. Pat. No. 5,340,433, U.S. Pat. No. 5,402,351, U.S. Pat. No. 5,503,785, U.S. Pat. No. 5,587,913, U.S. Pat. No. 5,738,817, U.S. Pat. No. 5,764,521 and U.S. Pat. No. 5,939,008. An extrusion head extrudes heated, flowable modeling material from a nozzle onto a base The base comprises a modeling substrate which is removably affixed to a modeling platform. The extruded material is deposited layer-by-layer in areas defined from the CAD model, as the extrusion head and the base are moved relative to each other in three dimensions by an x-y-z gantry system. The material solidifies after it is deposited to form a three-dimensional model. It is disclosed that a thermoplastic material may be used as the modeling material, and the material may be solidified after deposition by cooling.